Guard bed containing lead compounds upstream of a bed of copper-containing catalyst to prevent its contamination by chlorine and sulphur contaminants

Abstract

A combination comprising a bed of a particulate copper-containing catalyst and, a guard bed of a particulate composition containing a) lead and/or at least one lead compound that reacts with hydrogen chloride and b) a support therefor. The lead compound is preferably lead nitrate. The combination is of particular utility for the low temperature shift reaction wherein carbon monoxide is reacted with steam to produce hydrogen and carbon dioxide.

1. A process for performing a catalytic reaction involving hydrogen selected from the list consisting of hydrogenation reactions, methanol synthesis, methanol decomposition, the shift reaction and the reverse shift reaction, comprising passing a process gas containing carbon monoxide and steam through a guard bed of a particulate composition containing a) at least one lead compound, other than lead oxide, that reacts with hydrogen chloride and b) a support therefor, and then passing said process gas at a temperature in the range of 150-300° C. through a bed of copper-containing catalyst. 
     
     
       2. A process according to  claim 1  wherein the process gas further comprises at least one gas selected from the group consisting of hydrogen, carbon dioxide, methane, and nitrogen. 
     
     
       3. A process according to  claim 1  wherein the process gas is passed through the copper-containing bed at an inlet temperature in the range 150 to 250° C. 
     
     
       4. A process according to  claim 1  wherein the process gas contains 1 to 4% by volume of carbon monoxide, and at least one mole of steam per mole of carbon monoxide. 
     
     
       5. A process according to  claim 1  wherein the catalytic reaction is a shift reaction. 
     
     
       6. A process according to  claim 1  wherein the copper catalyst is selected from the list consisting of a copper/zinc oxide/alumina or copper/zinc oxide/chromia catalyst. 
     
     
       7. A process according to  claim 6  in which some of the zinc oxide is replaced by magnesia.